Hiroshima-shi, Japan
Hiroshima-shi, Japan

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PubMed | Hiroshima University, Gifu Prefectural Ena Agricultural High School, Kyoto University and Chuden Engineering Consultants Co.
Type: Journal Article | Journal: Applications in plant sciences | Year: 2016

Adenophora palustris (Campanulaceae) is an endangered wetland plant species in Japan. Although it is widely distributed in East Asia, only six extant populations are known in Japan, with fewer than 1000 individuals in total. We developed 15 microsatellite markers for this species and confirmed their utility for the closely related species A. triphylla var. japonica.Ten polymorphic loci were characterized for genetic variation within three populations of A. palustris. The number of alleles per locus ranged from four to 15, with an average of 9.3; the expected heterozygosity ranged from 0.48 to 0.89, with an average of 0.74. Nine loci were successfully amplified in A. triphylla var. japonica, and three of these loci showed polymorphism.These markers are useful for investigating genetic diversity and gene flow within and among remnant populations of A. palustris in Japan, and the results will provide crucial information for conservation.


Iwata N.,Chuden Engineering Consultants Co. | Sasaki T.,Suncoh Consultants Co. | Yoshinaka R.,Saitama University | Kurooka K.,Chugoku Electric Power Co.
International Journal of Rock Mechanics and Mining Sciences | Year: 2012

This paper describes the validity of the multiple yield model (MYM) based on a comparison between predictions by MYM analysis and in-situ measurements of two large-scale vertical excavations, about 30. m in depth and 100. m in width, for nuclear power plants. MYM is a finite element method for modeling the mechanical properties of intact rock and joint systems in rock mass. The method can analyze the non-linearity of deformation under loading and unloading stress paths. The analysis was conducted by determining the geometrical model of rock mass from test adit and borehole observations of discontinuities in conditions such as orientation, spacing, and persistence. The physical parameters of intact rock and discontinuities were determined by laboratory tests using sample specimens, taking the scale effect into account. The deformation mode and displacement value determined by the MYM analysis both corresponded well with in-situ measurements. We have confirmed that MYM can estimate the actual behavior of discontinuous rocks with adequate accuracy for practical application. © 2012 Elsevier Ltd.


Tsubota Y.,Chugoku Electric Power Co. | Iwakoke Y.,Chugoku Electric Power Co. | Yoshinaka R.,Saitama University | Yamaguchi K.,Chuden Engineering Consultants Co.
ISRM International Symposium - 8th Asian Rock Mechanics Symposium, ARMS 2014 | Year: 2014

The behavior of rock masses during an earthquake is greatly influenced by the geometrical distribution of discontinuities within the rock mass. Therefore, it is very important to accurately investigate them for stability features such as geological structures constructed on the rock foundation, rock slope etc. The static mechanical properties of rock joints such as shear strength, shear stiffness etc. have been studied so far. However, the dynamic properties that are necessary for the seismic response analysis have not been investigated as much as the static studies. Because the test equipment for seismic properties of rock joints have not been developed so far and there are too many parameters to seismic properties (dynamic properties) such as frequency effect, cyclic effect etc. The authors have developed practical dynamic test equipment and investigated fundamental dynamic mechanical properties of rock joints under cyclic loading using mortar specimens from this research until now. In this study, we conducted dynamic tests of natural rock joints focused on "Ryoke gneiss" which had not been investigated and reported the seismic properties of natural rock joints in detail for the first time. As a result, we have confirmed that the dynamic shear strength is nearly equal to the static strength, but this result does not seem appropriate to other natural rock joints and it is necessary to consider more detailed experiments after understanding the surface condition of rock joints. The only sure thing is that the shear strength of seismic properties is greatly affected by the surface condition of rock joints (ex. roughness, hardness, and degree of weathering). In other words, it is an important factor to investigate the surface condition of rock joints beforehand if we are going to understand seismic properties of rock joints. Through this study, knowledge of seismic properties of rock joints could be obtained and it would contribute greatly to the development of rock engineering. © 2014 by Japanese Committee for Rock Mechanics.


Iwata N.,Chuden Engineering Consultants Co. | Takahashi Y.,Chuden Engineering Consultants Co. | Sasaki T.,Suncoh Concultants Co. | Yoshinaka R.,Saitama University
ISRM International Symposium - 8th Asian Rock Mechanics Symposium, ARMS 2014 | Year: 2014

Dynamic response analysis is conducted to evaluate slope stability under seismic conditions for the surrounding slope at important structures such as main traffic routes, nuclear power plants etc. Stability analyses have generally used numerical analysis assuming that rock mass is elastic and homogeneous using the results from PS logging and/or the seismic coefficient method. However, the behavior of rock masses is greatly influenced by the geometrical distribution of discontinuities within the rock mass. The authors have proposed Multiple Yield Model (MYM), which is a type of finite element method constituting the mechanical properties of intact rock and discontinuity systems in a rock mass and introducing cyclic loading elastic-plastic deformation characteristics of rock joints. The applicability of this method was verified by making comparisons with the observed seismic waves in rock foundations under large structures during the 2011 Off the Pacific Coast of Tohoku earthquake and so on (Iwata et al., 2013). We indicate the necessity of considering discontinuities in rock masses on modeling of seismic response analysis. In this study, we conducted seismic response analysis of rock slopes using MYM and evaluated the influence of the geometrical distribution of discontinuities, such as dip angle and number of joint sets, and compared them with the traditional model described above. As a result, seismic response is strongly influenced by the distribution of discontinuities and the seismic response of MYM is distinctly different from one of elastic body. To assess the seismic response of a slope under earthquake conditions, it is necessary to conduct numerical analysis which considers the distribution and mechanical properties of discontinuities. © 2014 by Japanese Committee for Rock Mechanics.


Iwata N.,Chuden Engineering Consultants Co. | Sasaki T.,Suncoh Consultants Co. | Yoshinaka R.,Saitama University
Harmonising Rock Engineering and the Environment - Proceedings of the 12th ISRM International Congress on Rock Mechanics | Year: 2012

The authors are analyzed two practical examples of large scale vertical excavations 20-30m in depth and two earthquake response analyses of the discontinuous rock slope and rock foundation of large building, and are presented the applicability of MultipleYield Model (MYM). MYM is a kind of finite element method constituted the mechanical properties of intact rock and discontinuity systems in rock mass, and can be analyzed the non-linearity of deformation under loading and unloading stress paths considering the confining pressures of rock joints. For analyzing, the geometrical models of rock mass were determined from site investigations and the physical parameters were determined by laboratory test and also considering scale effect. The results of MYM analysis were well corresponded to the measurement and it is confirmed that MYM is effective for static and dynamic response on jointed rock masses. © 2012 Taylor & Francis Group, London.


Osanai N.,Japan National Institute for Land and Infrastructure Management | Shimizu T.,Public Works Research Institute PWRI | Kuramoto K.,Chuden Engineering Consultants Co. | Kojima S.,Fujikawa Sabo Office | Noro T.,Snow Avalanche and Landslide Research Center
Landslides | Year: 2010

Early-warning systems for natural disasters are important tools for disaster risk reduction and for achieving sustainable development and livelihoods. In 2005, the Japanese government initiated a new nationwide early-warning system for landslides disasters. The main methodology of the system is to set a criterion for occurrences of debris flows and slope failures based on several rainfall indices (60-min cumulative rainfall and soil-water index) in each 5-km grid mesh covering all of Japan. Because many of the records of mass movements are lacking in scientific precision on timing and location, the system applies Radial Basis Function Network methods to set the criterion based primarily on rainfall data recorded as not triggering disasters. Since the end of March 2007, under torrential rainfall conditions, early-warning information has been disseminated as part of weather news using TV, radio, and the Internet. Because of the increasing worldwide recognition of the importance of early-warning systems for natural disaster reduction, the aim of this article is to introduce the new Japanese early-warning system to the international landslide community. In this article, the method, the system, and the result of its application to landslide disasters in 2009 are presented. © 2010 Springer-Verlag.


Hyodo M.,Yamaguchi University | Noda S.,Yamaguchi University | Orense R.,University of Auckland | Furukawa S.,Chuden Engineering Consultants Co.
5th China-Japan Geotechnical Symposium | Year: 2013

As a result of the Great East Japan Earthquake, five slope failures occurred in a residential area on artificial valley fills in Taiyo New Town, Yamamoto, Miyagi Prefecture. The fill material is sandy, derived from the weathering of tuffaceous sandstone which formed the natural ground. Cyclic triaxial tests showed that the fill, which has about Fc= 20%, has very low liquefaction resistance, which decreased with application of initial shear stress. Thus, the slope failure in Taiyo New Town can be attributed to the liquefaction of the fill material induced by the intense shaking.


Mori A.,ESI Japan Ltd. | Ishida S.,Chuden Engineering Consultants Co. | Shinji M.,Yamaguchi University
40th International Congress and Exposition on Noise Control Engineering 2011, INTER-NOISE 2011 | Year: 2011

The main method to reduce the blasting charge noise which occurs in a tunnel under construction is to install the sound insulation door in the tunnel. However, the numerical analysis technique to predict the accurate effect of the transmission loss in the sound insulation door is not established. In this study, we measured the blasting charge noise and the vibration of the sound insulation door in the tunnel with the blasting charge, and performed analysis and modified acoustic feature. In addition, we reproduced the noise reduction effect of the sound insulation door by statistical energy analysis method and confirmed that numerical simulation is possible by this procedure.


Iwata N.,Chuden Engineering Consultants Co. | Yoshinaka R.,Saitama University | Sasaki T.,Suncoh Consultants Co.
International Journal of Rock Mechanics and Mining Sciences | Year: 2013

The stability, deformation behavior, permeability and other properties of discontinuous rocks are greatly influenced by the geometrical distribution of discontinuities in rock mass, and extremely important infrastructures such as nuclear power plants, large-scale underground excavations, long-span bridges, etc. built on or in discontinuous rock mass are also influenced by these same effects. However, a seismic analytical method such as for earthquake response, to correctly evaluate discontinuous conditions of rock mass has not been developed. This paper describes a new seismic response analytical method using the multiple yield model as a kind of FEM. The applicability of this method was verified by making comparisons between the seismographic records obtained with several underground deaths at The 2005 offshore Miyagi Prefecture Earthquake (MW=7.2) and The 2011 offshore the Pacific coast of Tohoku Earthquake (MW=9.0), both of which seismic motions were obtained at the same large and very important nuclear power plant, and the results of the response analyses using the seismic motions recorded at the deepest earth level of seismographs. The geological condition of the foundation ground is one of strongly folded hard sedimentary rocks. From this study, we have confirmed that the multiple yield model is an effective method for seismic response analysis. © 2013 Elsevier Ltd.


Iwata N.,Chuden Engineering Consultants Co. | Sasaki T.,Suncoh Consultants Co. | Sasaki K.,Suncoh Consultants Co. | Yoshinaka R.,Saitama University
Rock Mechanics in Civil and Environmental Engineering - Proceedings of the European Rock Mechanics Symposium, EUROCK 2010 | Year: 2010

This paper describes the validity of the MultipleYield Model to the earthquake response analysis of the discontinuous rock by two examples of the actual collapsed rock slope caused during the Mid Niigata Prefecture Earthquake in 2004 (M 6.8) and the large scale and/or very important facility like as a nuclear power station on rock. Results show that geometrical and mechanical conditions of joints have strong influence on the seismic response. © 2010 Taylor & Francis Group.

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